The present invention relates to a computer graphic process and, more particularly, to a method and apparatus for perspective-transforming a three-dimensional thing on a virtual two-dimensional screen.
In a conventional technique, when a three-dimensional object (thing) is perspective-transformed on a virtual two-dimensional screen, points for specifying the thing are respectively calculated in accordance with ratios of distances between a point of view and the points to a distance between the point of view and the screen to perform perspective transformation.
However, since the distances between the point of view and the respective points for specifying the thing are different from each other, very large amounts of calculation for the distances are required by the CPU (Central Processing Unit) or another device of a computer. In other words, in an entertainment system such as a video game apparatus, the heavy load on the CPU or the like is a problem when high-speed processing for an object image which continuously changes is performed.